With WGDs new arti filter in the 'Use' arti screens (which is epic, thanks WGD) I thought that maybe at the top left, opposite from the filter he might put a 'Stack' button.
While npcing with all buffs burning I find it takes a few seconds longer to scroll through the enemy artis to get to the sabs after killing heaps of Dark Traffickers and amassing heaps of Dark Void ACFs, it also take a few extra seconds to got to the Trade tab and stack them there. Also help full when reapplying a Neural Interface after amassing massive amounts of Crimson Obeliskd and Crimson Amplifiers. The way I see it anything that lets me keep killing efficiently is a good thing.
Any thoughts?

+1 however if you go into your trade part, then onto artifacts and press stack, it automatically stacks it on other windows aswell, but it would be a good idea to have it there for less clicking.

+0 from me, I will admit it is annoying, scrolling past all the ACFs, but the amount of time it takes you to go to the trade tab and stack them is nothing, that and how many times do you need to use debuffs on NPCs? Iso-runners, a few tough elites, not enough to make this important.